Document Detail

Role of surface tension and tissue in rat lung stress relaxation.
MedLine Citation:
PMID:  7111918     Owner:  NLM     Status:  MEDLINE    
When the volume of the lung is maintained constant after an initial change of volume, stress relaxation (SR) occurs as a slow decay of transpulmonary pressure (PTP). In order to define which structure in the lung is responsible for SR a multiple exponential fitting of the PTP variation has been made. Excised rat lungs were placed in a fluid-filled box with trachea connected to atmosphere and submitted to stepwise changes of volume. Single volume steps (0.2 ml) were performed for lungs filled with either air or saline and the variations of PTP were monitored until steady state was reached. An exponential model (time constant = 6.5 +/- 0.4 (SD) and 92 +/- 6 s) described adequately the SR for air-filled lungs (n = 6) whereas only one exponential (time constant = 6.7 +/- 1.3 s) was required for saline-filled lungs. Multiple volume step experiments were also performed in air-filled lungs to obtain pressure volume loops. These hysteresis loops have been adequately simulated by use of the exponential model. It can be concluded that (1) lung tissue and air-liquid interface are both responsible for the SR with, respectively, short and long time constants and (2) the same relaxation function is able to describe both stress relaxation and static hysteresis in such experimental conditions.
A M Lorino; A Harf; G Atlan; H Lorino; D Laurent
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Respiration physiology     Volume:  48     ISSN:  0034-5687     ISO Abbreviation:  Respir Physiol     Publication Date:  1982 Apr 
Date Detail:
Created Date:  1982-10-12     Completed Date:  1982-10-12     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0047142     Medline TA:  Respir Physiol     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  143-55     Citation Subset:  IM    
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MeSH Terms
Lung / physiology*
Lung Compliance*
Surface Tension

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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